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            <h2 class="title" style="clear: both"><a id="secondaryDelete"></a>Deleting Secondary Database Records</h2>
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      <p>
        In general, you 
             
            <span>will</span> 
        not modify a secondary database directly. In
        order to modify a secondary database, you should modify the primary
        database and simply allow DB to manage the secondary modifications for you.
    </p>
      <p>
        However, as a convenience, you can delete 
            
            <span>secondary database</span>
        records directly. Doing so causes the associated primary key/data pair to be deleted.
        This in turn causes DB to delete all 
            
            <span>secondary database</span>
        records that reference the primary record.
    </p>
      <p>
        You can use the 
            
            <code class="methodname">DB-&gt;del()</code>
            
        method to delete a secondary database record. 
        
        

        <span>Note that if your
            <span>secondary database</span> 
             
        contains duplicate records, then deleting a record from the set of
        duplicates causes all of the duplicates to be deleted as well.
        </span>

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      <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
        <h3 class="title">Note</h3>
        <p>
      
      <span>
        You can delete a secondary database record using the previously
        described mechanism
      </span>
      only if the primary database is opened for write access.
      </p>
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      <p>For example:</p>
      <a id="c_index7"></a>
      <pre class="programlisting">#include &lt;db.h&gt;
#include &lt;string.h&gt;

...

DB *dbp, *sdbp;    /* Primary and secondary DB handles */
DBT key;           /* DBTs used for the delete */
int ret;           /* Function return value */
char *search_name = "John Doe"; /* Name to delete */

/* Primary */
ret = db_create(&amp;dbp, NULL, 0);
if (ret != 0) {
  /* Error handling goes here */
}

/* Secondary */
ret = db_create(&amp;sdbp, NULL, 0);
if (ret != 0) {
  /* Error handling goes here */
}

/* Usually we want to support duplicates for secondary databases */
ret = sdbp-&gt;set_flags(sdbp, DB_DUPSORT);
if (ret != 0) {
  /* Error handling goes here */
}

/* open the primary database */
ret = dbp-&gt;open(dbp,        /* DB structure pointer */
                NULL,       /* Transaction pointer */
                "my_db.db", /* On-disk file that holds the database.
                             * Required. */
                NULL,       /* Optional logical database name */
                DB_BTREE,   /* Database access method */
                0,          /* Open flags */
                0);         /* File mode (using defaults) */
if (ret != 0) {
  /* Error handling goes here */
}

/* open the secondary database */
ret = sdbp-&gt;open(sdbp,          /* DB structure pointer */
                 NULL,          /* Transaction pointer */
                 "my_secdb.db", /* On-disk file that holds the database.
                                 * Required. */
                 NULL,          /* Optional logical database name */
                 DB_BTREE,      /* Database access method */
                 0,             /* Open flags */
                 0);            /* File mode (using defaults) */
if (ret != 0) {
  /* Error handling goes here */
}

/* Now associate the secondary to the primary */
dbp-&gt;associate(dbp,            /* Primary database */
               NULL,           /* TXN id */
               sdbp,           /* Secondary database */
               get_sales_rep,  /* Callback used for key creation. */
               0);             /* Flags */

/*
 * Zero out the DBT before using it.
 */
memset(&amp;key, 0, sizeof(DBT));

key.data = search_name;
key.size = strlen(search_name) + 1;

/* Now delete the secondary record. This causes the associated primary
 * record to be deleted. If any other secondary databases have secondary
 * records referring to the deleted primary record, then those secondary
 * records are also deleted.
 */
 sdbp-&gt;del(sdbp, NULL, &amp;key, 0); </pre>
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